Alloy



Patented Jan. 21, 1941 UNITED STATES PATENT OFFICE ALLOY tion of NewYork No Drawing.

Application October 21, 1939,

Serial No. 300,579

5 Claims.

This invention relates to alloys and is concerned more particularly witha novel gold alloy which is suitable for use in'the manufacture ofjewelry and is characterized by having a fine grain structure. The newalloy has greater hardness and resistance to Wear than standardcompositions heretofore used for similar purposes and also has increasedcorrosion'resistance. In addition, the new alloy is capable of beinghardened by appropriate heating and cooling treatments as well as bycold working, and by variation in the amounts of the constituentsemployed, it may be given different colors as well as different physicalproperties which vary in accordance with the 1d nature of the articlesinto which it is to be manufactured.

The new alloys may be made with varying amounts of gold, depending onthe karat desired. In general, it contains substantial amounts of gold,copper, and silver, and ordinarily a less amount of zinc. In addition,it contains a small quantity of iron. The proportions of theseconstituents will, of course, vary in accordance with the purposes forwhich the alloy is to be used, but ordinarily the proportions will fallwithin the ranges given in the following analysis in which the rangelimitations given are approximate.

Per cent Gold 35 to 75 Silver 5 to Copper 12 to Zinc 0.1 to 12 Iron 1 to5 it) A specific example of the new alloy, which is a ten karat gold, isof the following approximate analysis:

' Example No. 1

Per cent a Silver 25 Copper 32 Zinc 0.3 Iron l Another alloy embodyingthe principles of the invention and of fourteen karat is of thefollowing approximate analysis:

v Example No. 2 Per cent Gold 58.3 Silver 24.28 Copper 16.28 Zinc 0.14Iron 1 Other alloys embodying the principles of the invention and offourteen karat are given in the following examples:

As an indication of the efiect of appropriate heat treatments on suchalloys, the following data are given. An alloy of Example No. 2, after39 having been annealed at 1200" F. for one-half hour and then quenched,shows a Rockwell B hardness of and a scleroscope value of 30. Onreheating this alloy for one hour at 600 F., the Rockwell "13 hardnessincreases to 102 and the 35 scleroscope to 52.

The new alloy exhibits excellent physical properties and the addition ofiron does not materially change the color. Also, although the presenceof iron increases the hardness and wear 40 resistance of the alloy, theiron does not make it more difficult to fabricate. In general, anincrease in the iron content reduces the ductility and the quantity ofiron used will, therefore, depend on the purposes for which the alloy isto be 45 employed. The grain size of that form of the new alloycontaining from 2% to 5% iron is much smaller than that of those formsof the alloy containing only 1% iron. Above 2% iron, however, there isno marked grain size reduction 50 imparted by the higher iron content.It, therefore, appears that a form of the new alloy containing between1% and 2% iron would exhibit the optimum composition of grainrefinement, hardness, and ductility. as

In making up the new alloy, the constituents, other than iron and a partof the gold, are: melted and the iron introduced into the melt in theform of a master alloy containing 80% gold and 20% iron.

In addition to the physical properties previously mentioned, the newalloy is characterized by having a considerable resilience orspringiness, particularly when employed in the form of thin sections.Accordingly, it may he used to advantage in the production of articles,such as watch cases and vanity cases, in which the springiness of thealloy'causes it to resist deformation. Also, these characteristics makeit desirable for use in the production of pen points.

I claim:

1. An alloy which consists of gold in an amount ranging from about 35%to about'75%, silver in an amount ranging from about 5% to about copperin an amount rangingfrom about 12% to about zinc in an amount rangingfrom about 0.1% to about 12 and iron in an amount ranging from about 1%to about 5%.

2. An alloy which consists of at least 35% of gold, silver in an amountranging from about 5% to about 25%, copper in an amount ranging fromabout 12% to about 35%, zinc in an amount ranging from about 0.1% toabout 12%, and iron in an amount ranging from about 1% to about 5%.

3. An alloy which consists of about 41.7% gold, about 25% silver, about32% copper, about 0.3% zinc, and about 1% iron.

4. An alloy which consists of at least 58.3% gold, silver ranging fromabout 22.28% to about 24.28%, copper ranging fromabout 14.28% to about16.28%, about 0.14% zinc, and iron ranging from about 1% to about 5%.

5. An alloy which consists of about 58.3% gold, about 24.28% silver,about 16.28% copper, about 0.14% zinc, and about 1% iron.

ROBERT H. LEACH.

